Silicone Sealant vs. Caulk: What is the Difference?

In today’s applications the most common sealants are silicone and caulk. The two are highly effective sealants that perform exceptionally well in most applications.
However, there are certain variable that makes these sealants unique or suitable for certain uses.
In this guide, we will explore fundamental differences between these two sealants.

What is Silicone Sealant?

Silicone Sealant
Silicone Sealant

Silicone sealant, is at times referred to as silicone glue or silicone adhesive. It is an adhesive whose primary ingredient is silica and forms a watertight bond between surfaces.

What is Caulk?

Caulk is a special sealant made from acrylic and latex material. It forms a perfect sealant which is perfect for sealing air leaks, joints and gaps.


Composition of Caulk and Silicone Sealant

The main composition of silicone sealant is silicone polymer whose primary material is silica. This is alongside other additives that improve the binding property of silicone adhesive.

You will find that the composition of silicone sealant includes a base polymer, a curing agent that includes siloxane that does reacts with moisture to form a cured silicone rubber .

At times, you may also add fillers to provide strength, and plasticizers to help enhance its flexibility and workability.

Additionally it contains additives to prevent mold and mildew growth to enhance resistance and for color and solvent.

On the other hand, you will realize that caulk composition is quite different. A reason for unique properties and applications.

Caulk composition is mainly acrylic polymer as a base, and calcium carbonate as a filler. Additionally, you may add plasticizer to increase the flexibility, water that acts as a solvent, and additives that act as a pigment.

Comparison Properties of Silicone Sealant and Caulk


One of the most flexible sealants is made from silicon. However, the flexibility may vary depending on the prevailing conditions.

They are also best used in areas that are subjected to movement and vibration.

Your caulk flexibility varies depending on the type of caulk.

Examples include acrylic latex caulk is less flexible and can crack under movement. On the other hand, polyurethane caulk is highly flexible and mostly comparable to silicone in flexibility.


When it comes to durability, silicone sealant is more durable and it does not shrink.

It is also resistant to UV light and extreme temperatures. On the other hand, caulk can shrink and crack over time. To make it worse, it may be affected when exposed to sunlight.


If you are working on non-porous surfaces, then choose silicone sealant. Otherwise, caulk is a good adhesive to porous surfaces like wood, drywall, and masonry.

Silicone Adhesive Structure
Silicone Adhesive Structure


When it comes to painting, silicone sealant cannot be painted. On the other hand, you can use caulk on applications that require painting.

Water Resistance

If you are working on surface that require water resistance, then go for silicone sealant. Silicone sealants are highly waterproof. Therefore, these sealants are perfect choice for water prone areas such as kitchens, bathrooms and other outdoor applications.

On the other hand, the waterproof properties of caulk vary depending on the grade. Although acrylic latex caulk remains water resistant, it is not waterproof. Therefore, don’t use it in areas prone to water.

· Easy to Use

Silicone sealant is difficult to apply due to its stickness and requires a solvent to clean up while caulk is easy to apply and smooth. You can easily clean it up using water.

Curing Time

If you want a sealant that cures faster, then choose caulk. On the other hand, silicone sealant takes longer time to cure.

Applying Caulk
Applying Caulk

Silicone Sealant vs Caulk Application

1. Silicone Sealant Application.

Bathroom and Kitchen

Silicone sealant is used in sealing around sinks, bathtubs, and showers. It is also used to prevent water seepage and mold growth.

Windows and Doors

It is used to provide a water-light seal to keep out moisture and seal gaps to improve insulation and prevent drafts.

Outdoor Applications

Silicone sealant is used in sealing joints and gaps in siding, roofing, and gutters.

Automotive and Marine

Marine uses silicone sealant to seal boat parts and in automotive applications in sealing windshields and windows.


Silicone sealant is used in electronics to protect components from moisture and dust. It is used in sealing enclosures and cosmetics.

2. Uses of Caulk

Windows and Doors

Caulk is used in sealing around windows and door frames to help lessen air leaks and improve energy efficiency.


In plumbing applications, caulk is used in sealing around fixtures like sinks, toilets, and bathtubs.

Interior Gaps and Cracks

If you have small cracks on both walls and ceilings, or you intent to fill gaps in baseboards, then caulk offers a perfect option.

Exterior use

Due to its durability and resistance to weathering caulks used in roofing, sealing gaps inside and exterior windows and doors.


Both silicone sealant and caulk are used in sealing gaps and joints. They also contain different compositions and properties making it to be used in different applications as discussed below.

More resources :

Silicone Sealant vs. Acrylic – Source: LEGENDAY

Difference between Grout and Silicone Caulk – Source: LEGENDAY

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